There are many theories about what causes vitiligo, and no one is positively certain. However, experts are almost certain that a genetic predisposition or susceptibility to vitiligo exists in nearly all people who develop vitiligo.
Vitiligo may result from a number of factors -- autoimmune, oxidative stress (excess of hydrogen peroxide), neurotrophic (interaction of melanocytes and the nervous system), and toxic (substances formed as a part of normal melanin production actually being toxic to melanocytes) hypotheses have been advanced. The mechanism involves progressive destruction of selected melanocytes, probably by cytotoxic T-cell lymphocytes.
In most cases, it is believed that Vitiligo is a type of autoimmune disorder, in which the body's immune system sees the pigment cells in the skin as foreign bodies, and attacks them. The basis for this autoimmune disorder is thought by many to be genetic. It is believed by many that stress, traumatic events, injury, or severe sunburns, may trigger or exacerbate vitiligo in those who are susceptible.
Other theories include the possibility that an abnormally functioning nervous system may produce a substance that injures melanocytes. Some believe that melanocytes in vitiligo patients may self-destruct, releasing toxic byproducts that then destroy other pigment cells. Another theory suggests that vitiligo is entirely genetic, and that there is a defect in the melanocytes that makes them more susceptible to injury.
We know that some cases of vitiligo arise from exposure to certain chemicals, for example, phenols used in photography. Surgery wounds or injuries to the skin have also been known to result in vitiligo, which can spread. The question is, are those people susceptible to vitiligo to begin with. Many experts say yes.
Finally, there are alternative theories about vitiligo that suggest diet, nutrition, and digestive disorders may play a role in the destruction of melanocytes. Some believe that internal pathogens within the digestive tract, such as yeast proliferation, might relate to vitiligo.
What is a Melanocyte (Pigment Cell)?
A Melanocyte is a specialized cell located in the skin, which produces melanin (pigment). Surprisingly, all humans have roughly the same number of pigment cells in their skin. Those with darker toned skin, have pigment cells that are able to store more melanin within them. In the diagram below, the cell with the tendrils, marked "I" is the melanocyte. The brown color within the cell is the melanin. The cell uses the tendrils to distribute the melanin evenly throughout the skin.
What is Melanin?
Melanin is a dark brown pigment of skin and hair in animals, particularly vertebrates, derived from the amino acid tyrosine. It is synthesized by special cells called Melanocytes, which also store the melanin.